Method of making louvered ventilator



1965 L. SMITH ETAL 3,203,079

METHOD OF MAKING LOUVERED VENTILATOR Filed Jan. 26, 1961 s Sheets-Sheet 1 mmyrons .[esicr LSmzih 6 3y Frank Randall W W W Y aiiys Aug. 31, 1965 1.. SMITH ETAL METHOD OF MAKING LOUVERED VENTILATOR 5 Sheets-Sheet 2 Filed Jan. 26, 1961 /NVENTOR$.' Lester 1.. Smith 6' franb E. @andall 62M Y a1: is

Aug. 31, 1965 L. L. SMITH ETAL METHOD OF MAKING LOUVERED VENTILATOR Filed Jan. 26, 1961 3 Sheets-Sheet 3 .l'i f INVEMTORS lcsier LSm Q y Frank E. Ran Z My W M) United States Patent 3,203,079 METHOD 0F MAKING LOUVERED VENTILATOR Lester L. Smith, Peoria, Ill. (P1). Box 68, Prineevrlle,

Ill.), and Frank E. Randall, Peoria, Ill; said Randall,

assiguor to said Smith Filed Jan. 26, 1961, Ser. No. 85,108 9 Claims. (Cl. 29-1635) This invention relates to louvered ventilators and to a method of making such ventilators, and more particularly the invention is concerned with ventilators integrally made from sheet stock by a method and to embody structure such that the louvered sheet does not warp or bend as a result of the formation of the louvers and openings therein.

Subject matter disclosed herein, but not afforded adequate protection in this application, is disclosed and claimed in our copending application, Serial No. 414,292

for Louvered Ventilator, filed November 27, 1964.

The integral formation of louvered openings in sheet stock by usual methods and to embody customary structure sets up stresses in the sheet which cause the louvered sheet to bend or warp. This warping or bending of louvered sheets and strips is undesirable in practically any instance and makes it difiicult to secure a louvered ventilater in place relative to a flat surface. The stresses which cause the warping or bending result from the variations in the amount of deformation and the lack of symmetry of each louver in a direction lateral to the louver. Further- 'rnore, the stresses occur even though the sheet stock is clamped and held flat during the punching and forming operation.

One of the general objects of this invention is to provide a louver structure and a method of producing integrally formed louvers in sheet stock whereby the resulting louvered sheet will be normally flat.

As another object, this invention comprehends the provision of a method of producing louvers by which the material in each louver is coined in direct relation to the amount of deformation and elongation of the material during the forming operation, so as to relieve the stresses normally inherent as a result of such deformation and elongation.

The invention further has within its purview the provision of a method of producing integrally formed louvers in sheet stock wherein and whereby the material of each louver is varied in thickness during the forming operation to effect a flow of such material which is related to the amount of deformation and elongation of the metal and relieves the stresses normally caused by variations of the deformation and elongation across each louver and in comparison to the undeformed material.

As another object, this invention provides a method of producing louvered ventilators wherein each louver is prevented from delivering strain producing stresses to the rest of the ventilator structure without detriment to the strength, weather protection and such desirable characteristics of the ventilator.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a front elevational view of a louvered panel inegrally formed from sheet stock and wherein the structures of the louvers and the method in which the louvers are made are in accord with a preferred embodiment of this invention;

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FIG. 2 is a fragmentary front elevational view of a portion of the louvered panel depicted in FIG. 1 and drawn to a scale larger than that of FIG. 1 to afford a better illustration of the structural details involved;

FIG. 3 is a longitudinal sectional view taken substantially as indicated by a line 3-3 and accompanying arrows in FIG. 2;

FIGS. 4 and 5 are end section views taken substan tially at the positions indicated by lines 44 and 5-5 in FIG. 2 and in the directions indicated by the arrows;

FIG. 6 is a fragmentary top plan view of a preferred form of die adapted to use in our preferred method for the formation of louvers of the type illustrated in FIGS. 1 to 5 inclusive; the position and direction of the view being substantially as indicated by a line 66 and accompanying arrows in FIG. 8;

FIG. 7 is a fragmentary bottom view of a punch adapted to use with the die of FIG. 6, the view being taken substantially as indicated by a broken line 77 and accompanying arrows in FIG. 8;

FIG. 8 is a side sectional view showing sections at different positions along adjacent louver punches and dies, as indicated by a broken section line 8-8 and accompanying arrows in FIG. 6, and wherein the punch and die are seated with sheet material therebetween for the formation of louvers embodying a preferred form of our structure by our preferred method;

FIG. 9 is a front elevational view of a single punch of the type illustrated in FIGS. 7 and 8;

FIG. 10 is a fragmentary front sectional view of the seated louver forming punch and die with sheet material disposed therebetween;

FIG. 11 is a fragmentary top plan view similar to FIG. 6 and depicting a modified type of die adapted to use for making louvered sheets of the type herein disclosed; and

FIG. 12 is a fragmentary front sectional view similar to FIG. 10, but showing the die of FIG. 11 and a punch of the type shown in FIG. 7 With sheet material therebetween.

In the exemplary embodiment of our invention which is disclosed herein for illustrative purposes, we have illustrated the adaptation of our invention to a louvered panel 12 having therein a plurality of louvers 13 which, in the disclosed form, are substantially alike in structure and which are arranged in rows extending both longitudinally and laterally of the panel. The panel is integrally made of sheet stock material, which may be either metal, such as sheet aluminum or sheet steel, or some types of plastics. It may be understood that although the structure disclosed herein for illustrative purposes embodies a considerable number of relatively small louvers, the disclosed principles, method steps and the structural details are similarly applicable to structures wherein the louvers are larger in proportion to the area of the panel and are differently arranged, or may even be applicable to an individually formed louver which is adapted to mounting in reference to a fiat surface; it being understood that one of the problems solved by the disclosed structure and the use of our method is the relief of stresses in each three-dimensionally formed louver, in order to avoid the tendency of each louver to warp and thereby avoid the warping or bending of either an individual louver or a panel embodying any number of integrally formed louvers as a result of the cumulative stresses set up in the individual louvers.

As depicted, and as is usual, the louvers 13 project outwardly from one surface of the panel and are similarly disposed, so that each overlies a vent opening 14 in the panel, although it may be understood that our invention is not limited to louvers arranged in rows, as shown, or to those projecting from only one surface of a panel or sheet. In such structures, the material of the panel is pierced along a line which forms an edge 15 of the vent opening and longitudinal free edge 16 of the louver. Each louver comprises sheet material from the panel which is formed longitudinally and laterally of the longitudinal louver edge 16 to afford the desired longitudinal and lateral configuration of the louver. In the form herein illustrated, each louver has end portions 17 and 18 which are curved in reference to planes normal to the panel and which extend both longitudinally and laterally of the longitudinal louver edge 16. Each louver also has an integral mid-portion 19 which, as shown in FIG. 4, is generally straight in a direction lateral to the edge 16, and which is also generally straight in a direction parallel to the longitudinal edge 16.

In the usual and previously known maners of forming louvers of the general type, and without precautions and steps being taken for the relief of stresses produced in the forming operation as a result of the non-symmetrical lateral configuration of each louver and the required deformation of the stock which is greatest at the curved end regions of each louver, as well as by virtue of the normal resilience and resistance to deformation of the material from which louvers are usually made, stresses have usually been encountered which tend to effect, and usually do effect, warping or bending of the louver or a panel from conformity to a plane fit surface. Such warping and bending is not only detrimental to the handling of the resultant product in production and shipment, but is particularly detrimental to appearance and the securement of the louvered panel in place in reference to a flat surface, particularly when the louvered panel is large or in the form of a long strip.

In the structure herein illustrated and by the method herein described, there are distinct departures from the usual louver structure and from the forming method previously used which compensate for factors, such as the resilience of the sheet material and its resistance to deformation and which are calculated to be substantially proportional to the amounts of deformation at various parts or regions of the louver, thereby to minimize the stresses in each formed louver, with a result that the tendency of a louvered panel to warp or bend as a result of such stresses is virtually and practically eliminated. In the structure disclosed and by the disclosed method, the result is accomplished without material detriment to the strength or weather protection afforded by each louver.

As is apparent in the disclosed structure, and as previously mentioned, the end regions 17 and 18 of each louver, which are deformed in reference to transverse planes, are subjected to more drastic and greater deformation than the longitudinal mid-portion of the louver. Being formed both laterally and longitudinally of the free edge 16 of each louver, the end regions 17 and 18 develop stresses in directions both longitudinal and lateral to the free edge. It has been found that if sheet stock has slits put therein which will extend laterally of the free edge of each louver near the curved end regions thereof and then the louvers are formed in the usual and customary manner or if formed louvers of the usual type are cut laterally across the free edge 16 and near the end regions thereof, the cut slits will open longitudinally of the louver edge to form a V-shaped notch indicating the presence of longitudinal stresses in the louver and showing the desirability of greater longitudinal deformation toward the free edge to relieve such stresses.

While the desired longitudinal elongation may be provided at various positions along the louver and may be etfected at various times in respect to the forming of the louvers for relieving the aforementioned stresses in each louver, this elongation is effected in the disclosed louvers by coining the end regions 17 and 18 of each louver in a manner to effect a flow of the formed sheet material of the louver longitudinally thereof, and in amounts related to the amount of deformation of each increment of the louver from its preformed dimensions. By our preferred method, this coining is done at the end of the forming stroke of the louver punch. As shown in FIG. 3, the coining which is effected by our preferred method produces a gradual reduction of the thickness of the louver material from positions 20 and 22 near the juncture of the formed louver section with the unformed sheet stock and toward inner portions of the end regions, which are indicated as positions 23 and 24, at which the curved end portions 17 and 18 are adjoined to the relatively straight mid-portion 19 of the louver. Also, as shown in FIG. 5, the thickness ofeach louver end regions 17 and 18, as a result of the coining, diminishes outwardly toward the free edge 16 from a position 25 at which the formed section of the louver adjoin the unformed sheet tock. This coining relieves the stresses laterally of the free edge of the louver and in proportion to the variations of the amount of deformation of the louver section in a direction lateral to the free edge. It may be understood that the coining may be restricted to more localized areas longitudinally of the louvers, but is most effective when closely associated with the curved end regions of the louver.

As may be observed in FIG. 4, the thickness of the louver material laterally of the mid-portion 19 of each louver remains substantially uniform when suflicient elongation of the material is produced by the coining of the end regions 17 and 18. The coining of the material in or adjacent the end regions 17 and 18 of each louver effects variations of the louver thickness between end regions l7 and 18 of each louver and the opposite ends of the mid-portion 19 thereof, which variations of thickness increase toward and lateral to the free edge. By confining the thinned material to the curved end regions, the rigidifying effect to the curvatures of the formed end regions compensates for the weakening of the material section.

It has been found that the reduction of the material thickness in a direction inwardly from the opposite ends of the louver and laterally toward the free edge of the louver provides the desired elongation in proportion to the deformation of the louver and effects a flow of the material inwardly from the louver ends and toward the free edge which is desirable for relief of the stresses which otherwise tend to cause the louvers and their adjoining material to warp or bend.

By our preferred method, louvers of the type illustrated in FIGS. 1 to 5 inclusive are pierced, formed and coined from sheet stock by tools of the type illustrated in FIGS. 6 to 10 inclusive, or those shown in FIGS. 11 and 12. The tools shown in FIGS. 6 to 10 inclusive include a die 28 and a punch 29. In the form disclosed, the die 28 has a plurality of louver forming cavities 30 in which a plurality of louvers are simultaneously and individually formed in one piece of normally flat sheet stock. This die conforms to the exterior surfaces of the louvers, including the curved end regions thereof. The punch 29 has a plurality of individual louver forming punch elements 32 thereon which fit into the cavities 30 of the die 28 to effect the respective slitting, forming and coining operations in coaction with the die 28. Adjacent the louver forming punch elements, clamping blocks, such as 33, are mounted on the punch 29 and are supported by resilient means, such as compression springs 34, for gripping unformed marginal portions of the sheet stock to hold it in position against the surface of the die during the punching, forming and coining operations and to aid in stripping the formed sheet material from the punch.

As shown in FIGS. 6 and 10, the cavities 30 of the die are generally smooth with substantially straight midregions 35 and smoothly curved end regions 36, while end regions 37 and 38 of each louver forming punch element 32, as shown in FIGS. 7, 9 and 10, are raised in varying amounts above the level of a mid-portion 39 of each punch element, in order to accomplish the coining operation at the end of the forming stroke of the punch by compression of the material of the end regions 17 and 18 of the louvers between the punch elements and the die. The contours of the raised end regions of each punch element are calculated to produce the coining required for effecting the sectional louver shapes and sectional thicknesses depicted in FIGS. 3 and 5. That is, the end regions of the punch elements are raised above the midportion of the punch element more at positions 40 and 42 adjacent the free edge of each formed louver than they are adjacent laterally the opposite edge of each formed louver. Also, as may be observed in FIG. 10, the curvatures of the end portions of the punch and die are not concentric, whereupon the thickness of the material therebetween is varied toward the thinner section at the positions at which the end regions of the formed louvers adjoin the mid-portions thereof.

In the modified tools illustrated in FIGS. 11 and 12, the forming and coining operations are accomplished by the coaction of the punch 29 with a die 43 having cavities 44 which present substantially fiat and angularly disposed forming surfaces 45, which forming surfaces extend the full width of the die cavities, and are not curved at .the ends to conform to the curvatures of the outer surfaces of the punched louvers. With this type of die, the punch determines the configurations of the end portions 17 of the louvers. It is to be observed, also, that with the type of die depicted in FIGS. 11 and 12, the coining of the metal in the end portion of each louver is confined to an area of variable width laterally of the louver in which the metal is compressed between the end regions 37 and 38 of the pu'nch and the opposed surfaces of the die. As illustrated in FIG. 12, the punch 29 is seated within its die cavity 44 and the sheet material of the louver is compressed between the die surface and the end portions of the punch in areas 46 and 47 which extend from the inner edges of the raised end portions of the punch to positions at which the normal outer curvature of the louver material becomes tangent to the die surface. In order to proportion the widths of the coined areas to the amount of extension required in the formed material, the width of the coined area becomes narrower from the free edge of each louver toward the unformed portion thereof at which it adjoins the flat sheet stock. The ultimate result is similar to that obtained with the punch and die arrangement illustrated in FIGS. 6 to inclusive, but the coined areas of each louver are confined to shorter portions of the lengths of the curved end regions, and consequently the depths of the coined areas are slightly greater than those of the first described form, in order to obtain the required elongation in the curved end areas of each louver.

From the foregoing description and by reference to the accompanying drawings, it may be readily understood that we have produced a louver structure and a method of producing louvers which provide for the relief of stress in the formed material and thereby result in the production of louvers or louvered panels which are adapted to conform to a flat surface without being warped or bent to effect such conformity. It is noteworthy that our disclosed structure and the method afford louvers which provide normal rigidity and which have normal weather protective characteristics.

It is further to be understood in connection with this invention that the principles of our method and the resultant structural advantages are applicable, even though various kinds of cutting and forming tools may be utilized in place of the exemplary types depicted and described herein.

Having thus described our invention, what is claimed is:

1. The method of integrally forming louvers from sheet stock which have end regions curved in transverse planes,

which method comprises the steps of punching the sheet stock along a line to define a longitudinal louver edge and an edge of a vent opening, forming the louver to project outwardly from the plane of the sheet stock and to provide regions at opposite longitudinal ends thereof which are curved in planes transverse to one another, and coining the said curved end regions of the louver during said forming to vary the thickness of the stock in said curved end regions, thereby to effect elongations of said curved end regions in amounts related to the required elongation of the louver stock in relation to the normal dimensions of the sheet stock.

2. The method of integrally forming louvers from sheet stock as defined in claim 1, and wherein said coining of the curved end regions of the louver during the forming varies the thickness of the stock in said curved end regions so that it becomes thinner in section in directions inwardly from the ends of the louver edge and parallel thereto as Well as toward the louver edge and transversely thereof.

3. The method of integrally forming louvers from sheet stock as defined in claim 1, and wherein said forming and coining produce relatively abrupt changes in the thickness of the louver material between said curved end regions of the louver and the portion of the louver between said curved end regions, which changes in thickness diminish in depth in a direction away from said louver edge and transverse thereto.

4. The method of integrally forming louvers from sheet stock as defined in claim 1, and wherein said coining of the curved end regions of the louvers varies in amount over the areas of those end regions and effects a flow of the material of the louver stock both longitudinally and laterally of the louver edge.

5. The method of integrally forming louvers from sheet stock to produce substantially fiat louvered panels having louvers projecting from the plane of the panel and adjoined thereto at opposite ends and longitudinally of the louver, which method comprises the steps of slitting the sheet stock internally of its edges to define a longitudinal edge of a louver and an edge of a vent opening, forming the louver longitudinally and laterally of said longitudinal edge thereof to effect the projection of the louver from the plane of the adjacent sheet stock, and coining a region of the louver along said longitudinal edge thereof to effect an elongation of the formed louver stock adjacent said longitudinal edge of the louver.

6. The method of integrally forming louvers from sheet stock as defined in claim 5, and wherein said coining of a region of the louver is effected during the final portion of the forming of the louver.

7. The method of integrally forming louvers from sheet stock as defined in claim 5, and wherein said coining of a region of the louver varies the thickness of the stock in the said region both laterally and longitudinally of said longitudinal edge of the louver.

8. The method of integrally forming louvers from sheet stock as defined in claim 5, and wherein said forming and coining produce an offset in one of the louver surfaces adjacent the coined region and extending laterally of the longitudinal edge of the louver and which offset diminishes in depth with the distance from said longitudinal edge of the louver.

9. In the method of integrally forming louvers from sheet stock to produce substantially fiat louvered panels, which method comprises the steps of piercing and forming the sheet stock to provide louvers projecting from one face of the stock and each having a longitudinal edge, and coining the sheet stock of each louver adjacent a portion of said longitudinal edge to effect an elongation thereof beyond that produced by the forming.

References Cited by the Examiner UNITED STATES PATENTS Re. 19,477 2/35 Dixon et al.

(Other references on following page) 7 UNITED STATES PATENTS Hoxie et a1.

Goodwin et a1 113-49 X Schuster et a1. 29-548 X Gruetjen 113-116 Smith 98-121 Wintriss 29-548 X Smith et a1. 113-116 Smith 113-116 8 2,855,841 10/58 Smith ct a1. 98-121 2,937,985 6/61 Johnson 98-121 FOREIGN PATENTS 609,416 9/48 Great Britain.

WHITMORE A. \VILTZ, Primary Examiner.

CHARLES OCONNELL, JOHN F. CABEPBELL,

Examiners. 

1. THE METHOD OF INTEGRALLY FORMING LOUVERS FROM SHEET STOCK WHICH HAVE END REGIONS CURVED IN TRANSVERSE PLANES, WHICH METHOD COMPRISES THE STEPS OF PUNCHING THE SHEET STOCK ALONG A LINE TO DEFINE A LONGITUDINAL LOUVER EDGE AND AN EDGE OF A VENT OPENING, FORMING THE LOUVER TO PROJECT OUTWARDLY FROM THE PLANE OF THE SHEET STOCK AND TO PROVIDE REGIONS AT OPPOSITE LONGITUDINAL ENDS THEREOF WHICH ARE CURVED IN PLANES TRANSVERSE TO ONE ANOTHER, AND COINING THE SAID CURVED END PORTIONS OF THE LOUVER DURING SAID FORMING TO VARY THE THICKNESS OF THE STOCK IN SAID CURVED END REGIONS, THEREBY TO EFFECT ELONGATIONS OF SAID CURVED END PORTIONS IN AMOUNTS RELATED TO THE REQUIRED ELONGATED OF THE LOUVER STOCK IN RELATION TO THE NORMAL DIMENSIONS OF THE SHEET STOCK. 